Now, I've thought often about the character of Two-Face; he's one of my favorites. In fact, I've written about him on this blog several times. Unlike most people, what I was anticipating in the Dark Knight film wasn't Ledger's performance as the Joker (the trailers were pretty solid clues about that), but Eckhart's performance as Two-Face, and what the script would give him to work with.
Yes, Ledger's take on the Joker was very important and powerful. But the Joker's reputation as a solid character didn't necessarily rely on Ledger doing well. If Ledger had not acquitted himself so finely, it would have been taken as a reflection on Ledger, not the Joker. But Two-Face needed to be done well in this film to establish a broader public reputation as a serious Batman villain. He may be almost as famous as the Joker within the comic book world, but the only exposure to him most people have had is Tommy Lee Jones' performance in Batman Forever, which didn't really do the character justice.
But how do you do a character like Two-Face justice? First and foremost: don't portray him as a split personality. He wasn't portrayed that way when he was introduced, and to do so vastly oversimplifies and weakens the character. The Ventroliquist/Scarface is a split personality. Harvey Dent is a man whose concepts of morality have broken down and Two-Face is the man who forges a new concept of morality to work from. As I have said before, Two-Face isn't Harvey Dent's problem, he's Harvey Dent's solution. And, with unexpected wisdom, Christopher Nolan wrote Two-Face exactly that way. That alone makes the Dark Knight a great film in my eyes (although, there are certainly many other reasons, as well).
Note only did Dark Knight's Two-Face meet my high hopes it exceeded them; it taught me something about Two-Face, it gave me a perspective on him I'd never had before. Someone finally showed me that Harvey Dent is a perfectionist and a control freak.
Gordon's men aren't "pure" enough for him, even though they're helping Gordon and him clean up Gotham. His effort to clean up Gotham gangs isn't just about justice, it's about tidiness and control. Remember the courtroom scene with Rachel, where he plays -- lies, really -- about letting Rachel take charge of the case if his coin comes up tails? It won't, of course, because it's a two-headed coin. It's rather a cruel trick to play on her; I mean, is that really an appropriate thing to do to ones co-worker and fiancee? Dent uses the coin as a mechanism of control, or, as he puts it, he "makes his own luck". He doesn't believe in luck, or fate, or chaos; only control.
And, like a good attorney, he works the law to his advantage, redefining justice in a way that suits his purposes. The biggest example is the hat trick of the use of RICO laws against the Gotham gangster. His pointless grilling of the asylum lunatic he captures is another; "This is craziness," Batman points out, "you can't control it through sheer force of will." But even trying to gain control of the Joker situation by claiming that he is Batman is an example of Dent's need to control everything with his own plans.
Now, I'm not saying that's bad per se; but it doesn't work out perfectly well for Harvey, does it? In his comic book origin, it's the scarring of his face that sends him around the bend, as a perfectionist pretty boy like Dent isn't well equipped for such a thing (if anyone is). In the filmic origin, it's the essential unfairness of what happens to him, his own failure, that undoes him. He did everything he could to control the situation; but he couldn't. He couldn't "make his own luck", and he doesn't know how to handle a world where he can't be in control. Thus, the Joker easily seduces him into adapting by abandoning control of his decision and abrogating them to a flip of his coin.
The coin releases Dent from further moral dilemmas. It creates a form of "justice" -- or, at least, the fairness of even odds -- that seems more adapted to this world he now sees he cannot control, where justice cannot always be forcibly imposed. It's not something he's tied to, or controlled by; it's something he uses to relieve himself from the burden of controlling the world. The relief is very evident in the scene where he put a gun to his own head to decide whether he lives or dies to pay for his role in Rachel's demise. There's no tension at all in the decision, it's no more difficult for him then deciding whether to shoot Batman or Gordon's kid.
Of course, Two-Face isn't an entirely different person than Harvey Dent, and how he uses the coin is proof of that. I remember being shocked when the coin spared Maroni; "Wait," I thought, "Is Two-Face just going to let Maroni go with equanimity? That's hard to believe!" Of course, he didn't. Having abided by the coin flip, he immediately redefined the process to get his own way, and shot Maroni's driver (thus killing Maroni). Two-Face, like Harvey Dent, still works the system. He still manipulates others and the world, he's just let go of controlling himself.
